A poll released by Rasmussen Reports on Wednesday finds U.S. Rep. Connie Mack, the heavy favorite to win the Republican nomination, has a solid lead over Democrat incumbent U.S. Sen. Bill Nelson in Florida.

The poll of likely voters finds 46 percent backing Mack while Nelson lags behind with 37 percent. While 10 percent are undecided, 7 percent say they support other candidates in the race. Other polls have shown a closer contest, however; a Rasmussen poll in April had the numbers reversed with Nelson taking 47 percent and Mack trailing with 36 percent.

The poll of 500 likely voters was taken on July 9 and had a margin of error of +/- 4.5 percent.